Apparatus and method for monitoring state of cryogenic freezer

ABSTRACT

Disclosed is an apparatus and a method for monitoring a state of a cryogenic freezer, the apparatus and the method being capable of determining a door ajar state, a power-off state, and an abnormal state of the first and the second compressors based on temperatures sensed by first, second, and third temperature sensors respectively mounted to a front lower surface of the cryogenic freezer and refrigerant pipes adjacent to outlets of the first and the second compressors, and displaying the states through a display unit and a mobile terminal when the cryogenic freezer is in the states. The apparatus for monitoring the state of the cryogenic freezer of the present invention includes: a first temperature sensor; second and third temperature sensors; a controller; and an output unit.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No. 10-2015-0135507, filed Sep. 24, 2015, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to an apparatus and a method for monitoring a state of a cryogenic freezer, wherein the cryogenic freezer stores human derived biomaterials of a subject (blood, serum, plasma, and DNA), laboratory resources, such as plants, animals, microorganisms, and the like, and vaccines, at a temperature −4° C. or lower. More particularly, the present invention relates to an apparatus and a method for monitoring a state of a cryogenic freezer, whereby the apparatus and method are capable of determining a door ajar state, a power-off state, and an abnormal state of the first and the second compressors based on temperatures sensed by first, second, and third temperature sensors respectively mounted to a front lower surface of the cryogenic freezer and refrigerant pipes adjacent to outlets of the first and the second compressors, and displaying the states through a display unit and a mobile terminal when the cryogenic freezer is in the states.

Description of the Related Art

Generally, hospitals or laboratories use a cryogenic freezer that generates cool air at a temperature of −4° C. or lower in order to store human derived biomaterials of a subject (blood, serum, plasma, and DNA), laboratory resources, such as plants, animals, microorganisms, and the like, and vaccines.

For example, a cryogenic freezer, as disclosed in Korean Patent No. 1329345, includes: a compressor compressing refrigerant into a high temperature and high pressure refrigerant; a condenser condensing the high temperature and high pressure refrigerant; a gas-liquid separator having first and second gas-liquid separators separating a mixed refrigerant condensed into two layers, into a gaseous refrigerant and a liquid refrigerant; a heat exchanger having first and second heat exchangers supplying a low temperature and low pressure liquid refrigerant by spraying the liquid refrigerant of the gas-liquid separator to be expanded, and supplying the gaseous refrigerant after it's condensed by heat exchange with the liquid refrigerant to next gas-liquid separator; an evaporator obtaining cryogenic cold by expanding the refrigerant that is supplied from a final gas-liquid separator and is condensed through a final heat exchanger; and a refrigerant retrieval passage allowing the refrigerant having passed through the evaporator to be retrieved to the compressor.

A conventional cryogenic freezer configured as described above is problematic in that when something is wrong with the power supply or a performance problem occurs due to deterioration of accompanied equipment, a sample of a subject is highly likely to be spoiled, so it is required to constantly monitor a state of the freezer.

Further, the conventional cryogenic freezer configured as described above is configured such that a plurality of temperature sensors is mounted inside the freezer (namely, to a compartment of the freezer) to monitor a state of the freezer. The inside of the cryogenic freezer is sealed, so even if something is wrong with the freezer, the inside of the freezer remains cold for a predetermined time (about, 8 to 10 hours), and after the predetermined time, the temperature inside the freezer rises immediately. Thus, even if problems, such as a power-off state occurs, the freezer remains within a range of predetermined temperature for a predetermined time due to the effect of refrigerant, but after the predetermined time the temperature inside the freezer rises dramatically because the effect of refrigerant disappears. When the temperature inside the freezer rises dramatically, even though the temperature sensors sense temperature changes and then take a measure for obtaining the effect of refrigerant, the refrigerant that has no effect constantly raises the temperature for a while, and accordingly it takes long time to obtain a desirable cooling effect, and thereby medicines or articles stored in the freezer may be spoiled.

The foregoing is intended merely to aid in the understanding of the background of the present invention, and is not intended to mean that the present invention falls within the purview of the related art that is already known to those skilled in the art.

DOCUMENTS OF RELATED ART

(Patent Document 1) Korean Patent No. 1329345

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind the above problems occurring in the related art, and the present invention is intended to propose an apparatus and a method for monitoring a state of a cryogenic freezer, whereby the apparatus and method are capable of accurately determining a state of the freezer when changes occur without being influenced by a sealed structure of the freezer, that is, without being influenced by the effect of refrigerant inside the freezer, and immediately notifying the changes such that an action is immediately taken.

In order to achieve the above object, according to one aspect of the present invention, there is provided an apparatus for monitoring a state of a cryogenic freezer, the cryogenic freezer including: a first compressor compressing refrigerant into a high temperature and high pressure gaseous refrigerant; a condenser condensing the high temperature and high pressure gaseous refrigerant received from the first compressor into a low temperature and high pressure liquid refrigerant; a vapor filter connected to an outlet of the condenser and functioning to remove moisture of a refrigerant passage; a second compressor compressing a low temperature and low pressure gaseous refrigerant into a high temperature and high pressure gaseous refrigerant; a heat exchanger discharging the refrigerant to the first compressor by processing the refrigerant received from the vapor filter by heat exchange, and discharging a low temperature and high pressure liquid refrigerant by processing the refrigerant received from the second compressor by heat exchange; and an evaporator vaporizing the low temperature and high pressure liquid refrigerant received from the heat exchanger into a low temperature and low pressure gaseous refrigerant and discharging the gaseous refrigerant to the second compressor, wherein the apparatus for monitoring the state of the cryogenic freezer includes: a first temperature sensor mounted to a front lower surface of the cryogenic freezer and sensing a temperature; second and third temperature sensors respectively mounted to refrigerant pipes adjacent to outlets of the first and the second compressors and sensing temperatures of the refrigerant; a controller detecting temperatures by using the first, the second, and the third temperature sensors, comparing the detected temperatures to first, second, and third preset values, and determining a door ajar state, a power-off state, and an abnormal state of the first and the second compressors by determining whether the detected temperatures fall within a predetermined normal temperature range, wherein when the cryogenic freezer is in at least one of the states, the controller outputs control signals corresponding to the states; and an output unit receiving the control signals from the controller, and outputting images or voices corresponding to the signals.

In the apparatus, the controller may be configured to inform a mobile terminal of a state of the cryogenic freezer when the cryogenic freezer is in at least one of the door ajar state, the power-off state, and the abnormal state of the first and the second compressors.

In order to achieve the above object, according to another aspect of the present invention, there is provided a method for monitoring a state of a cryogenic freezer, the method including: a first step of sensing temperatures of predetermined locations by the first, the second, and the third temperature sensors; a second step of determining whether a temperature sensed by the third temperature sensor is higher than the third preset value; a third step of determining whether a temperature sensed by the second temperature sensor is higher than the second preset value when the temperature sensed by the third temperature sensor is higher than the third preset value in the second step; a fourth step of determining whether a temperature sensed by the first temperature sensor is lower than the first preset value when the temperature sensed by the second temperature sensor is higher than the second preset value in the third step; and a fifth step of displaying a door ajar state of the freezer through the output unit and the mobile terminal when the temperature sensed by the first temperature sensor is lower than the first preset value in the fourth step.

The method may further include a sixth step of displaying an abnormal state of the freezer through the output unit and the mobile terminal when the temperature sensed by the first temperature sensor is higher than the first preset value in the fourth step.

The method may further include: after the first step, a seventh step of determining whether the temperature sensed by the first temperature sensor falls within the predetermined normal temperature range; an eighth step of determining whether the temperature sensed by the second temperature sensor falls within the predetermined normal temperature range when the temperature sensed by the first temperature sensor falls within the predetermined normal temperature range in the seventh step; a ninth step of determining whether the temperature sensed by the third temperature sensor falls within the predetermined normal temperature range when the temperature sensed by the second temperature sensor falls within the predetermined normal temperature range in the eighth step; and a tenth step of displaying a power-off state of the freezer through the output unit and the mobile terminal when the temperature sensed by the third temperature sensor falls within the predetermined normal temperature range in the ninth step.

In the method, when the temperature sensed by the third temperature sensor does not fall within the predetermined normal temperature range in the ninth step, the sixth step may be implemented.

The method may further include: after the first step, an eleventh step of determining whether the temperature sensed by the second temperature sensor falls within the predetermined normal temperature range; a twelfth step of determining whether the temperature sensed by the third temperature sensor falls within the predetermined normal temperature range when the temperature sensed by the second temperature sensor falls within the predetermined normal temperature range in the eleventh step; and a thirteenth step of displaying an abnormal state of the first and the second compressors through the output unit and the mobile terminal when the temperature sensed by the third temperature sensor falls within the predetermined normal temperature range in the twelfth step.

The method may further include a fourteenth step of displaying an abnormal state of the first compressor through the output unit and the mobile terminal when the temperature sensed by the third temperature sensor does not fall within the predetermined normal temperature range in the twelfth step.

The method may further include: a fifteenth step of determining whether the temperature sensed by the third temperature sensor falls within the predetermined normal temperature range when the temperature sensed by the second temperature sensor does not fall within the predetermined normal temperature range in the eleventh step; and a sixteenth step of displaying an abnormal state of the second compressor through the output unit and the mobile terminal when the temperature sensed by the third temperature sensor falls within the predetermined normal temperature range in the fifteenth step.

According to an embodiment of the present invention, the apparatus and the method for monitoring a state of a cryogenic freezer are configured such that: temperatures of predetermined locations are sensed by the first, the second, and the third temperature sensors respectively mounted to a front lower surface of the cryogenic freezer and refrigerant pipes adjacent to outlets of the first and the second compressors, and when temperatures sensed by the third and the second temperature sensors are higher than third and second preset values respectively and a temperature sensed by the first temperature sensor is lower than a first preset value, a door ajar state of the freezer is displayed; when the temperatures sensed by the first, the second, and the third temperature sensors fall within the predetermined normal temperature range, a power-off state of the freezer is displayed; when only a temperature sensed by the second temperature sensor falls within the predetermined normal temperature range, an abnormal state of the first compressor is displayed; when only a temperature sensed by the third temperature sensor falls within the predetermined normal temperature range, an abnormal state of the second compressor is displayed; and when only the temperatures sensed by the second and third temperature sensors fall within the predetermined normal temperature range, an abnormal state of the first and the second compressors is displayed, and thereby the apparatus and the method are capable of accurately determining a state of the freezer when changes occur without being influenced by a sealed structure of the freezer, that is, without being influenced by the effect of refrigerant inside the freezer, and immediately notifying the changes such that an action is immediately taken.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating an overall configuration of an apparatus for monitoring a cryogenic freezer according to the embodiment of the present invention;

FIG. 2 is a view illustrating an example where a first temperature sensor shown in FIG. 1 is mounted to a front lower surface of the cryogenic freezer;

FIG. 3 is a view illustrating an example where second and third temperature sensors shown in FIG. 1 are mounted to refrigerant pipes adjacent to outlets of the first and the second compressors;

FIGS. 4a and 4b are flowcharts illustrating a method for monitoring a cryogenic freezer realized by the apparatus for monitoring the cryogenic freezer according to the embodiment of the present invention; and

FIG. 5 is a graph illustrating variations in temperatures sensed by the first, the second, and the third temperature sensors in response to a state of the cryogenic freezer according to the embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinbelow, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Throughout the drawings, the same reference numerals will refer to the same or like parts.

FIG. 1 is a block diagram illustrating an overall configuration of an apparatus for monitoring a cryogenic freezer according to the embodiment of the present invention; FIG. 2 is a view illustrating an example where a first temperature sensor shown in FIG. 1 is mounted to a front lower surface of the cryogenic freezer; and FIG. 3 is a view illustrating an example where second and third temperature sensors shown in FIG. 1 are mounted to refrigerant pipes adjacent to outlets of the first and the second compressors.

As shown in FIG. 3, a cryogenic freezer, which is applied to the present invention, includes: a first compressor 10 compressing refrigerant into a high temperature and high pressure gaseous refrigerant; a condenser 20 condensing the high temperature and high pressure gaseous refrigerant received from the first compressor 10 into a low temperature and high pressure liquid refrigerant; a vapor filter 30 connected to an outlet of the condenser 20 and functioning to remove moisture of a refrigerant passage; a second compressor 40 compressing a low temperature and low pressure gaseous refrigerant into a high temperature and high pressure gaseous refrigerant; a heat exchanger 50 discharging the refrigerant to the first compressor 10 by processing the refrigerant received from the vapor filter 30 by heat exchange, and discharging a low temperature and high pressure liquid refrigerant by processing the refrigerant received from the second compressor 40 by heat exchange; and an evaporator 60 vaporizing the low temperature and high pressure liquid refrigerant received from the heat exchanger 50 into a low temperature and low pressure gaseous refrigerant and discharging the gaseous refrigerant to the second compressor 40.

As shown in FIGS. 1 to 3, the apparatus for monitoring a cryogenic freezer according to the embodiment of the present invention includes first, second, and third temperature sensors 110, 120, and 130, a controller 200, and an output unit 300.

The first temperature sensor 110 is mounted to a front lower surface U of the cryogenic freezer, and senses temperatures. The first temperature sensor 110 senses a temperature lower than a first preset value (hereinbelow, used as a reference value for determining a door ajar state) since cold air flows down when a door D is ajar, and senses a temperature that falls within a predetermined normal temperature range (about 20° C.) in a power-off state (see FIG. 5).

A second temperature sensor 120 is mounted to a refrigerant pipe adjacent to an outlet of the first compressor 10 and serves to sense a temperature of the refrigerant. The second temperature sensor 120 senses a temperature higher than a second preset value (hereinbelow, used as a reference value for determining a door ajar state) when the door D is ajar, and senses a temperature that falls within the predetermined normal temperature range in a power-off state or an abnormal state of the first compressor 10 (see FIG. 5). The reason why the second temperature sensor 120 senses a temperature higher than the second preset value when the door D is ajar is that the first compressor 10 is overly operated to lower a temperature of the evaporator 60 when the door D is ajar.

A third temperature sensor 130 is mounted to a refrigerant pipe adjacent to an outlet of the second compressor 40 and serves to sense a temperature of the refrigerant. The third temperature sensor 130 senses a temperature higher than a third preset value (hereinbelow, used as a reference value for determining a door ajar state) when the door D is ajar, and senses a temperature that falls within the predetermined normal temperature range in the power-off state or an abnormal state of the second compressor 40 (see FIG. 5, but the abnormal state of the second compressor not shown in the drawings). The reason why the third temperature sensor 130 senses a temperature higher than the third preset value when the door D is ajar is that the second compressor 40 is overly operated to lower the temperature of the evaporator 60 when the door D is ajar.

A controller 200 detects temperatures by using the first, the second, and the third temperature sensors 110, 120, and 130, compares the detected temperatures to first, second, and third preset values, and determines a door D ajar state, a power-off state, and an abnormal state of the first and the second compressors 10 and 40 by determining whether the detected temperatures fall within a predetermined normal temperature range, wherein when the cryogenic freezer is in at least one of the states, the controller outputs control signals corresponding to the states to an output unit 300 and functions to inform a mobile terminal 400. The controller 200 may communicate with the mobile terminal 400 wirelessly or by wire.

The output unit 300, as a device for receiving the control signals from the controller 200, and outputting images or voices corresponding to the control signals, outputs an alarm display and a warning sound particularly in a door D ajar state, a power-off state, and an abnormal state of the first and the second compressors 10 and 40.

The controller 200 and the output unit 300 may be constituted by microprocessor, PC (Personal Computer), laptop computer, smart phone, or the like.

Hereinbelow, reference will be made to a method for monitoring a cryogenic freezer using the apparatus for monitoring a cryogenic freezer configured as described above according to the embodiment of the present invention.

FIGS. 4a and 4b are flowcharts illustrating a method for monitoring a cryogenic freezer realized by the apparatus for monitoring the cryogenic freezer according to the embodiment of the present invention, and S refers to a step.

Firstly, temperatures of predetermined locations are sensed by the first, the second, and the third temperature sensors 110, 120, and 130 (S1).

In step 2 (S2), the controller 200 determines whether a temperature sensed by the third temperature sensor 130 is higher than the third preset value.

When the temperature sensed by the third temperature sensor 130 is lower than the third preset value in step 2 (S2) (NO), step 2 (S2) is repeated. On the contrary, when the temperature sensed by the third temperature sensor 130 is higher than the third preset value (YES), step 3 (S3) is implemented, wherein the controller 200 determines whether a temperature sensed by the second temperature sensor 120 is higher than the second preset value.

When the temperature sensed by the second temperature sensor 120 is lower than the second preset value in step 3 (S3) (NO), step 3 (S3) is repeated. On the contrary, when the temperature sensed by the second temperature sensor 120 is higher than the second preset value (YES), step 4 (S4) is implemented, wherein the controller 200 determines whether a temperature sensed by the first temperature sensor 110 is lower than the first preset value.

When the temperature sensed by the first temperature sensor 110 is lower than the first preset value in step 4 (S4) (YES), step 5 (S5) is implemented, wherein the controller 200 displays a door ajar state of the freezer through the output unit 300 and the mobile terminal 400.

Meanwhile, when the temperature sensed by the first temperature sensor 110 is higher than the first preset value in step 4 (S4) (NO), step 6 (S6) is implemented, wherein the controller 200 displays an abnormal state of the freezer through the output unit 300 and the mobile terminal 400.

Meanwhile, after step 1 (S1), the controller 200 determines whether the temperature sensed by the first temperature sensor 110 falls within the predetermined normal temperature range (S7).

When the temperature sensed by the first temperature sensor 110 does not fall within the predetermined normal temperature range in step 7 (S7) (NO), step 7 (S7) is repeated. On the contrary, when the temperature sensed by the first temperature sensor 110 falls within the predetermined normal temperature range (YES), step 8 (S8) is implemented, wherein the controller 200 determines whether the temperature sensed by the second temperature sensor 120 falls within the predetermined normal temperature range.

When the temperature sensed by the second temperature sensor 120 does not fall within the predetermined normal temperature range in step 8 (S8) (NO), step 8 (S8) is repeated. On the contrary, when the temperature sensed by the second temperature sensor 120 falls within the predetermined normal temperature range (YES), step 9 (S9) is implemented, wherein the controller 200 determines whether the temperature sensed by the third temperature sensor 130 falls within the predetermined normal temperature range.

When the temperature sensed by the third temperature sensor 130 falls within the predetermined normal temperature range in step 9 (S9) (YES), step 10 (S10) is implemented, wherein the controller 200 displays a power-off state of the freezer through the output unit 300 and the mobile terminal 400.

Meanwhile, when the temperature sensed by the third temperature sensor 130 does not fall within the predetermined normal temperature range in step 9 (S9) (NO), step 6 (S6) is implemented.

Meanwhile, after step 1 (S1), the controller 200 determines whether the temperature sensed by the second temperature sensor 120 falls within the predetermined normal temperature range (S11).

When the temperature sensed by the second temperature sensor 120 falls within the predetermined normal temperature range in step 11 (S11) (YES), step 12 (S12) is implemented, wherein the controller 200 determines whether the temperature sensed by the third temperature sensor 130 falls within the predetermined normal temperature range.

When the temperature sensed by the third temperature sensor 130 falls within the predetermined normal temperature range in step 12 (S12) (YES), step 13 (S13) is implemented, wherein the controller 200 displays an abnormal state of the first and the second compressors 10 and 40 through the output unit 300 and the mobile terminal 400.

Meanwhile, when the temperature sensed by the third temperature sensor 130 does not fall within the predetermined normal temperature range in step 12 (S12) (NO), step 14 (S14) is implemented, wherein the controller 200 displays an abnormal state of the first compressor 10 through the output unit 300 and the mobile terminal 400.

Meanwhile, when the temperature sensed by the second temperature sensor 120 does not fall within the predetermined normal temperature range in step 11 (S11) (NO), step 15 (S15) is implemented, wherein the controller 200 determines whether the temperature sensed by the third temperature sensor 130 falls within the predetermined normal temperature range.

When the temperature sensed by the third temperature sensor 130 does not fall within the predetermined normal temperature range in step 15 (S15) (NO), step 15 (S15) is repeated. On the contrary, when the temperature sensed by the third temperature sensor 130 falls within the predetermined normal temperature range (YES), step 16 (S16) is implemented, wherein the controller 200 displays an abnormal state of the second compressor 40 through the output unit 300 and the mobile terminal 400.

The apparatus and the method for monitoring a state of a cryogenic freezer according to the embodiment of the present invention are configured such that: temperatures of predetermined locations are sensed by the first, the second, and the third temperature sensors respectively mounted to a front lower surface of the cryogenic freezer and refrigerant pipes adjacent to outlets of the first and the second compressors, and when temperatures sensed by the third and the second temperature sensors are higher than third and second preset values respectively and a temperature sensed by the first temperature sensor is lower than a first preset value, a door ajar state of the freezer is displayed; when the temperatures sensed by the first, the second, and the third temperature sensors fall within the predetermined normal temperature range, a power-off state of the freezer is displayed; when only a temperature sensed by the second temperature sensor falls within the predetermined normal temperature range, an abnormal state of the first compressor is displayed; when only a temperature sensed by the third temperature sensor falls within the predetermined normal temperature range, an abnormal state of the second compressor is displayed; and when only the temperatures sensed by the second and third temperature sensors fall within the predetermined normal temperature range, an abnormal state of the first and the second compressors is displayed, and thereby the apparatus and the method are capable of accurately determining a state of the freezer when changes occur without being influenced by a sealed structure of the freezer, that is, without being influenced by the effect of refrigerant inside the freezer, and immediately notifying the changes such that an action is immediately taken.

The embodiments disclosed in the present invention are not restrictive but are illustrative, and the scope of the technical idea of the present invention is not limited to the embodiments. Therefore, it should be understood that the present invention is not limited to the embodiments but may be variously changed without departing from the technical idea of the present invention.

Accordingly, the scope of the present invention should be interpreted by the accompanying claims, and it is to be understood that all technical ideas within the claims fall within the purview of the present invention.

[Description of reference characters of important parts] 10: first compressor 20: condenser 30: vapor filter 40: second compressor 50: heat exchanger 60: evaporator D: door H: handle U: front lower surface of 300: output unit cryogenic freezer 110: first temperature sensor 120: second temperature sensor 130: third temperature sensor 200: controller 400: mobile terminal 

1. An apparatus for monitoring a state of a cryogenic freezer, the cryogenic freezer comprising: a first compressor compressing refrigerant into a high temperature and high pressure gaseous refrigerant; a condenser condensing the high temperature and high pressure gaseous refrigerant received from the first compressor into a low temperature and high pressure liquid refrigerant; a vapor filter connected to an outlet of the condenser and functioning to remove moisture of a refrigerant passage; a second compressor compressing a low temperature and low pressure gaseous refrigerant into a high temperature and high pressure gaseous refrigerant; a heat exchanger discharging the refrigerant to the first compressor by processing the refrigerant received from the vapor filter by heat exchange, and discharging a low temperature and high pressure liquid refrigerant by processing the refrigerant received from the second compressor by heat exchange; and an evaporator vaporizing the low temperature and high pressure liquid refrigerant received from the heat exchanger into a low temperature and low pressure gaseous refrigerant and discharging the gaseous refrigerant to the second compressor, wherein the apparatus for monitoring the state of the cryogenic freezer comprises: a first temperature sensor mounted to a front lower surface of the cryogenic freezer and sensing a temperature; second and third temperature sensors respectively mounted to refrigerant pipes adjacent to outlets of the first and the second compressors and sensing temperatures of the refrigerant; a controller detecting temperatures by using the first, the second, and the third temperature sensors, comparing the detected temperatures to first, second, and third preset values, and determining a door ajar state, a power-off state, and an abnormal state of the first and the second compressors by determining whether the detected temperatures fall within a predetermined normal temperature range, wherein when the cryogenic freezer is in at least one of the states, the controller outputs control signals corresponding to the states; and an output unit receiving the control signals from the controller, and outputting images or voices corresponding to the signals.
 2. The apparatus of claim 1, wherein the controller informs a mobile terminal of a state of the cryogenic freezer when the cryogenic freezer is in at least one of the door ajar state, the power-off state, and the abnormal state of the first and the second compressors.
 3. A method for monitoring a state of a cryogenic freezer using the apparatus of claim 1, the method comprising: a first step of sensing temperatures of predetermined locations by the first, the second, and the third temperature sensors; a second step of determining whether a temperature sensed by the third temperature sensor is higher than the third preset value; a third step of determining whether a temperature sensed by the second temperature sensor is higher than the second preset value when the temperature sensed by the third temperature sensor is higher than the third preset value in the second step; a fourth step of determining whether a temperature sensed by the first temperature sensor is lower than the first preset value when the temperature sensed by the second temperature sensor is higher than the second preset value in the third step; and a fifth step of displaying a door ajar state of the freezer through the output unit and the mobile terminal when the temperature sensed by the first temperature sensor is lower than the first preset value in the fourth step.
 4. The method of claim 3, further comprising a sixth step of displaying an abnormal state of the freezer through the output unit and the mobile terminal when the temperature sensed by the first temperature sensor is higher than the first preset value in the fourth step.
 5. The method of claim 3, further comprising: after the first step, a seventh step of determining whether the temperature sensed by the first temperature sensor falls within the predetermined normal temperature range; an eighth step of determining whether the temperature sensed by the second temperature sensor falls within the predetermined normal temperature range when the temperature sensed by the first temperature sensor falls within the predetermined normal temperature range in the seventh step; a ninth step of determining whether the temperature sensed by the third temperature sensor falls within the predetermined normal temperature range when the temperature sensed by the second temperature sensor falls within the predetermined normal temperature range in the eighth step; and a tenth step of displaying a power-off state of the freezer through the output unit and the mobile terminal when the temperature sensed by the third temperature sensor falls within the predetermined normal temperature range in the ninth step.
 6. The method of claim 5, wherein when the temperature sensed by the third temperature sensor does not fall within the predetermined normal temperature range in the ninth step, the sixth step is implemented.
 7. The method of claim 3, further comprising: after the first step, an eleventh step of determining whether the temperature sensed by the second temperature sensor falls within the predetermined normal temperature range; a twelfth step of determining whether the temperature sensed by the third temperature sensor falls within the predetermined normal temperature range when the temperature sensed by the second temperature sensor falls within the predetermined normal temperature range in the eleventh step; and a thirteenth step of displaying an abnormal state of the first and the second compressors through the output unit and the mobile terminal when the temperature sensed by the third temperature sensor falls within the predetermined normal temperature range in the twelfth step.
 8. The method of claim 7, further comprising: a fourteenth step of displaying an abnormal state of the first compressor through the output unit and the mobile terminal when the temperature sensed by the third temperature sensor does not fall within the predetermined normal temperature range in the twelfth step.
 9. The method of claim 7, further comprising: a fifteenth step of determining whether the temperature sensed by the third temperature sensor falls within the predetermined normal temperature range when the temperature sensed by the second temperature sensor does not fall within the predetermined normal temperature range in the eleventh step; and a sixteenth step of displaying an abnormal state of the second compressor through the output unit and the mobile terminal when the temperature sensed by the third temperature sensor falls within the predetermined normal temperature range in the fifteenth step. 